The use of optically detectable labeling groups, and particularly those groups having high quantum yields, e.g., fluorescent or chemiluminescent groups, is ubiquitous throughout the fields of analytical chemistry, biochemistry and biology. In particular, by providing a highly visible signal associated with a given reaction, one can better monitor that reaction as well as any potential effectors of that reaction. Such analyses are the basic tools of life science research in genomics, diagnostics, pharmaceutical research, and related fields.
To date, such analyses have generally been performed under conditions where the amounts of reactants are so far in excess that any adverse effects of the optical event would be unnoticed. For example, such analyses based upon fluorescent labeling groups generally require the use of an excitation radiation source directed at the reaction mixture, to excite the fluorescent labeling group, which is then separately detectable. However, prolonged exposure of chemical and biochemical reactants to such light sources, alone, or when in the presence of other components, e.g., the fluorescent groups, can lead, potentially, to damage to such reactants, e.g., proteins, enzymes, substrates, or the like. As noted previously, however, the existing formats for such reactions generally prevents any such effects from being problematic, or even being noticed.
A variety of analytical techniques are being explored, however, that deviate from the previous formats, such that detrimental effects of such photodamage will have a more dramatic impact on the operation of the given analysis. In particular, real time analyses of reactions that include fluorescent reagents can expose multiple different components to optical energy. Additionally, reactions based upon increasingly smaller amounts of reagents, e.g., in microfluidic or nanofluidic reaction vessels or channels, or in “single molecule” analyses. As such, the present invention is directed at methods and compositions that prevent or mitigate to some extent, the adverse effects of such photodamage, and also to processes that benefit from such methods and/or compositions, among other useful processes and compositions.